Automatic temperature regulator



March 3, 1931.

A. CHAGNAUD AUTOMATIC TEMPERATURE REGULATOR Filed Nov. 2, 1927 Mec/mmsm 7'0 56 C0 frol/eab.

MM) rcu/U [five/2Z0) Q H. lzaynaud ATTORNEYS Patented Mar. 3, 1931 NlTED STATES PATENT, OFFICE ANDRE CHAGNAUD, OF PARIS, FRANCE, ASSIGNOB T LES ETABLISSEMENTS POULENC FBEBES, A CORPORATION OF FRANCE AUTOMATIC TEMPERATURE REGULATOR Application filed November 2, 1927, Serial No. 230,576 and in France November 3, 1928.

T he present invention relates to automatic temperature regulators and, more particularly, to those of the type having a galvanometric control.

improve the form of contacts controlled by the ,galvanometer needle and leading to the heating circuit so as to increase the sensitive-, ness and reliability of the control device.

A further object-is to provide a galvanometrically controlled regulator capable of being connected to any ordinary lighting circuit and operating correctly even when vibrated.

Still. further objects will appear in the course of the detailed description now to be given with reference to the accompanying drawings, in which:

Fig. l is a diagram showing the galvanometer needle and an oscillatable control bar forming part of the device;

Fig. 2 is a diagram of one form of a makeand-break device forming part of the invention, the relays being omitted but the relay terminal connections being indicated by the arrow heads; and

Fig. 3 is a diagram of a modified form of make-and-break device connected to the locking circuits designed to prevent a second closure of the heating circuit until other operations to be described first take place.

Referring to the various figures of the drawing, there is shown a needle A forming part of a galvanometer (not shown) which is connected in circuit with a thermoelectric couple located in a chamber, or in contact with a material, whose temperature ,is to be regulated. B is a bar of substantially U- shaped formation positioned in parallel relation to scale or dial P of the galvanometer and capable of oscillating about wa: as an axis. Bar B carries a fixed stud f" for cooperating with contact f formed of suitable resilient material and carried by the dial P or in any other suitable manner-so as to be normally held out of contact with the contact f fixed to the dial when f" is not hearing on 7, but adapted to close contacts f and f when bar B lowers sufiiciently to cause f to press 50 downwardly on f, and a movable contact Gf One of the objects of the invention is to comprising the contacts 9 and g being formed of resilient material similar to f and being fixed to G in any suitable manner to be normally held out of contact with g), G" being capable of being displaced along the bar. Contacts f and f control the devices that close the heating circuit, while contacts 9 and g function to open said circuit or to diminish the amount of heat being supplied. By moving contact G" along bar is maintained in continureplaced by that of a spring or of an electromagnet. When the too hot contact G" bears on a small cone A mounted on needle A, contacts g, 9 close. lVhen cone A moves away from the too hot contact G", i. e. when the needle moves into the too cold region, bar B is capable of moving further downward and will thus close the too cold contacts 7 and f. The needle is' prevented from moving beyond the too hot contact by a stop a. I

Contact G" carries a small knife-edge S on its lower side against which cone A of needle A .may slide and which insures proper sensitiveness for the device. If during downward movement of bar B cone A is under knifesedge S, it will have to slide either to the right or to the left, i. c. it will either close the too hot contacts 9, g or permit closure of the too cold contacts f, f to take place. The position of knife-edge S, therefore, determines the constant temperature control. The position of the contacts themselves becomes secondary importance. The too cold contaci's f, f may, consequently, be removed to a distance and rendered fixed.

In prior devices of the present type, temperature control has been obtained by permitting the galvanometer needle to abut against one or the other of pair of too hot and too cold contacts mounted in the path of movement of the needle. The opening and closure of the heat control circuits in such constructions is uncertain and unreliable and the least vibration suffices to disturb the accuracy of temperature control.

In the present construction, as above described, this uncertainty and unreliability are done away with. The various contacts are made positively and under pressure and there is,therefore, no possibility of error. Contact f is fixed and incapable of movement, while contact G" only causes an insignificant movement of needle A when the base of cone A rests on graduated dial P. Needle A, it will be noted, is incapable of being distorted and its hearings will, therefore, remain intact indefinitely.

The system for moving bar B consists of a bimetallic strip L, fixed at one extremity M and inserted inside a resistance E connected to a sourceof current (independent of the pyrometer circuit) through the intermediary of a relay such as is shown in Fig. 3. The

free extremity 1 of strip L moves upward or a downward (according to whether current flows or does not flow through resistance E and whether the metal that has the greatest coeflicient of expansion is on the top or bottom of the bimetalic strip) between a pair of contacts 2, 3 whose justed. I

In the spring form of intermediary connection betweenthe strip L and the bar extremity B, shown in Fig. 2, the bimetallic strip L is position may be a positioned to deform upwardly when heated and counterweight H is placed as shown in Fig. 1. However, in the form shown in Fig. 3, the strip L is positioned to deform downwardly when heated and counterweight H is placed on theopposite side of the axis mw from its position in Fig. -1, that is, it is slid on B forwardly so that the counterweight always tends to close the contacts connected to terminals F, F or G, G, as the case may be, and deformation of L tendsto open them. In this latter form contact 2 is connected to the master. relay or locking system shown in Fig. 3 at the terminal F contact 3 being connected at G';,, and the stationary end of the strip M being connected at F Heating coil -E is connected across 1 (o' and the source of control power is connected to 11 I/ In the form shown in Fig. 2 the connections for the heating coil and the bimetallic strip are the same as in Fig. '3except that contact 2 is connected at G and cont-act 3 is connected at F because in this form of construction the strip L is postioned to deform upwardly when heated.

Extremity 1 will, it is evident, oscillate ter, and (4) by the distance between 2 and 3. Extremity 1 either bears against the free end B of bar B to raise the latter or releases the bar and permits it to rest on the control contacts. If desired, the alternate contact of 1 with 2 and 3 may be utilized to actuate one or a pair of electromagnets properly positioned to actuate bar B.

If the circuit used for actuating the various regulating elements is to be the same as that used for heating resistance E, the wires maybe properly connected to give the result desired.

The locking system shown as part of.

' (resistances and the like) a magnet 23, acting on a bar 21 whose free extremity is arranged to engage with the bar 22 of another electromagnet 24. Bar 21 tends to move away from 23, while 22 has the same tendency relatively to'24. Terminals F and G are connected to g and g respectively which are controlled by the galvanometer needle in the manner already described; one contact 9 is common to both terminals F and G.

If the chamber or article whose tempera-' ture is to be regulated is too cold, needleA swings to the leftv (Figs. 1, 2 and 3) and. con-' d tact f, f is established. Bar 21 is then either free or interengages with bar 22. In the event. that it is free, it. contacts at 17, closes circuit w, F, 23, 17 21, p, excites magnet 23, which attracts bar 21, thus making contact at 16 and closing the'circuitip, 21, 16, (0 controlling the various heating elements. Bar 22 of magnet 24, being normally held, away from magnet 24 when the said magnet is not excited, has a shoulder formed on its outer extremity which engages bar 21 of magnet 23 as bar 21 contacts with 16, thereby looking it in this position. Now, as the temperature of the devices which this mechanism controls increases, the needle A swings to the right and contact 9, g is established due to the deformation of the bimetallic strip L caused by the heating coil E. This heating coil is connected at w m' of a second relay or locking system called the master relay of the bar, which is a duplicate of the first mentioned locking system called the regulating relay; which is, connected to terminals F, F and G, G. When contacts 9, g are closed, magnet 24 is energized through circuit [1, 21, 16, 24, G, G, e, p, the source of power being connected to p, 4/. This energizing of magnet 24 causes the magnet to attract bar'22 which releases bar 21. and opens the circuit 16,

and this causes the heating control mechanisms connected at w, w'to dnmmsh or completely shut off the heat in the system. Thus it will be seen that any sparking due to opening and closingthe power circuits is taken at the contacts 16 and 1'1 and not at the contacts 7, f and g, g on the galvanometer, this being one of the many distinct advantages 6 over the ordinary form of control devices of this type.

The structures connected to w, w for heating do not begin to function if g, g is closed; thus, a plurality of successive contacts at g, 9' will not cause any trouble. In the same way repeated contacts at f, 7" will have no effect until contact- 9, g is made. The part of the device operates, therefore, in the manner of a locking or safety system.

T he operation of this system is as follows: Assuming the heating system being controlled by this invention is too cold (taking for example the form of construction shown in Fi 3, the strip L straightens to its uppermost position and allows bar B to lower, andv needle A, being in a position toward the left of the scale indicating low temperature, it allows contacts f, f to close under the action of the counterweight H (H being on theforward side of axis w-w in this form of'the device), 1 This causes the regulating relay to energize magnet 23 momentarily, which inturn attracts bar 21 andlocks it in contact with contact 16 by virtue of the latching of bar 22 over bar 21.. This energizes the control mechanisms connected to w, m which in turn start. up @the heating system or other device. Now, while these operations are taking place (it being understood that strip L isin its uppermost position) the free extremity 1 of strip L contacts with 2, which energizes magnet 23' of the master relay, locking bar 21' into contact with 16 and energizing the heating coil E .connected to (D w' The strip begins to deform downwardly and raises bar B opening contacts f, f without sparking v(since the regulatingrelay is still locked closed) and needle A begins to move to the right, indicating rising temperature in the heating system. After strip L is heated suth'ciently by coil E to cause 1 to contact with i 3, the master relay magnet 24 operates to release her 21 and open the circuit of the heating coil E, now allowing strip L to straighten out again, which'caus'es B to descend; During this time the heating system is stiliturned on and the needle has now moved under the contacts 9, g"or-sufiiciently far to cause S to engage A and force the nee- :dle under the contacts. By this time the bar from thepre ceding explanation applicable to Fig. 3, remembering that in Fig. 2 the strip deforms upwardly to lower bar B as before,

but the closing of contacts 1 and 3 causes heating coil E to be energized to subsequently eause the strip to deform upwardly.

' It will, of course, be obvious to those skilled in the art that lamp controls which respond to heating and cooling operations may be associated with. the foregoing apparatus and that the apparatus may be used in any situation where a motor or similar machine is to be operated or stopped in accordance with the reading of a galvanometer or similar indicating instrument.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is 2- 1. In a device of the class described, an

oscillatable means operable in conjunction with said needle to control the opening of said circuit, and means operable by the said oscillatable means for closing said circuit when out of contact with the needle.

2. in a device of theclass described, an instrument indicating needle, a circuit having elements therein capable of doing work, oscillatable means operable in conjunction with said needle to control the opening and closing of said circuit, and thermally controlled means for controlling the oscillation of said oscillatable means.

3. In a device of the class described, an in strument indicating needle, a. circuit having elements therein capable of doing work, an oscillatable bar, spaced contacts associated with said,bar and operable to open saidcircuit by hearing on said needle to cause said contacts to engage each other, and means for oscillating said bar.

p 4. in a device of the class described, an in strument indicating needle, control circuits having elements therein operable to control. heating elements, an oscillatable-bar, a, fixed contact'element and a movable contact for said control circuits mounted on said bar, said movable contact being adapted to contact with said needle, and means for oscillating said bar.

' 5. In a device of the class described, an instrument indicating needle, an instrument dial, a fixed control contact associated with said dial, an oscillatable bar, a fixed contact mounted on-said bar opposite said fixed con-- tact for the dial, a pair of contacts adjustably mounted on said bar, one of said contacts being positioned so as to be able to contact instrument indicating needle, a circuit havlng elements therein capable of doing work,-

with said needle during escillationio'f the bar,

and means for oscillating said bar.

6. In a device of the class described, an in'.

strunient indicatingneedle, a pair of circuits controlling a heating element, an oscillatable bar, a fixedcontact associated with said bar and operable to control one of said pair of circuits, a pair of movable contacts mounted on said bar and connected to the second of said pair of circuits, one of said movable contacts being positioned so as to be able to contact with said needle; means for oscillating said bar, :and means for preventing a second closure of one of the pair of circuits until the other circuit is first opened.

7. In a device of the class described, a bar oscillator comprising a bimetallic strip fixed at one end and carrying a contact at the other end thereof, a resistance wire positioned near the strip, a pair .of contacts positioned on opposite sides of the contact carried by the strip, and means operable to cut off the flow of current to said resistance wire.

8. In a device of the class described, an in strument indicating needle, a circuit having elements therein capable of doing work, a circuit closer included in said circuit, and

oscillatable meansoperable to actuate the circuit closer for effecting a closing of the circuit when the needle is out of coacting relation with the oscillatable means, said oscillatable means being adapted to coact with the needle without passing current through said needle to effect breaking of the circuit established by said circuit closer.

9. In a device of the class described, an instrumemt indicating needle, a circuit having elements. therein capable of doing work, circuit closing means in said circuit, an oscillatable means to actuate the circuit closer when the needle is in one position, said needle in another position coacting with said oscillatable means without passing current through said needle tobreak the circuit established by said circuit closer, and means for controlling the oscillation of said oscillatable means.

10. In a device of the class described, an instrument indicating needle, a circuit having elements therein capable of doing work, circuit closing means in said circuit, an oscillatable means to actuate the circuit closer when the needle is in one position, said needle in another position coacting with said oscillatable means without passing current through said needle to break the circuit established by said circuit closer, and thermally controlled means for controlling the oscillation of said oscillating means.

11. In a device of the class described, an instrument indicating needle, a circuit having elements therein capable of doing work, including circuit closing means, circuit breaking means, and a member coacting with the circuit closing'means to close the circuit aforesaid in one position of the needle and in another position' of the needle to coact with the circuit breaking means to interruptsaid circuit without passing current through said needle.

12. In a device of. the class described, an instrument indicating needle, a circuit having elements therein capable of doing work,

a circuit closer for said circuit, independent T circuit breaking means for interrupting said circuit, oscillatable means for efl'ect-. ing closing ofthe circuit through said circuit closer in one position of the needle. and for interrupting the circuit through said circuit breaking means under the control of the needle", without passing current through said needle, a thermallycontrolled device, and an auxiliary circuit in which said thermally controlled device is included operable incident to the interruption of the first mentioned circuit.

13. In a device of. the class described, an instrument indicating ,needle, a pair of circuits for controlling a heating element, an oscillat'able bar, a fixed contact associated with said bar and operable to control one of said pair of circuits, a member slidable on said a bar and carrying a pair of contacts operable to control the other of said pair of circuits, said pair of contacts being adapted to engage each other incident to movement of the indicating'needle therebeneath and lowering of said oscillatable bar to exert pressure on said contacts by the said needle, and means formed on said slidable member and said needle for deflecting said needle incident to lowering of the slidable bar when the'needle is in a zone immediately adjacent to the pair V of contacts carried by said slidable member.

14; In a device of the class described, an

instrument indicating needle, a pair of circuits for controlling a heating element, an

oscillatable bar, a fixed'contact associated with said bar and operable to control one of said pair of circuits, a member slidable on said bar and carrying a pair of contacts operable to control the other of said pair of circuits, saidpair of contacts being adapted to engage each other incident to movement of the indicating needle therebeneath and lowering of said oscillatable bar to exert pres-. sure on said contacts by the said needle, and means formed on said slidable member and said needle for deflecting said needle inci- 1 dent to lowering of the slidable bar when the needle is in a zone immediately adjacent to v the pair of contacts carried by said slidable member, said means comprising a knife edge on said slidable member and a conical mem ber carried by saidneedle. l i

In testimony whereof I afiix my signature.

ANDRE CHAGNAUD. 

